A new rearrangement product of thebaine, isolated from Papaver bracteatum Lindl. Structural assignment of thebaine N-oxides

Abstract

From Papaver bracteatum an unusual alkaloid is isolated: 6,7,8,9,10,14hexadehydro-4,5-epoxy-3,6-dimethoxy-17-methylthebinan (1 ). This alkaloid is also obtained from the mixture of rearrangement products of one of the thebaine N-oxides. The structure of another constituent of the latter mixture is deduced to be 6,7,8,9,10,14-hexadehydro-3,6-dimethoxythebinan-4-ol (1 5). The presence of both thebaine N-oxides in Papaver bracteatum is confirmed, and their structures are revised on chemical and spectroscopic grounds.

Rapid Assembly of Functionalized Hydrodibenzofurans via Semipinacol Rearrangements

“…While these approaches have tremendously facilitated the target oriented synthesis via linear synthetic routes, a convergent method that could allow for the diverse variation of the R group is rare (Figure ). Moreover, while synthetic methods for the preparation of fused indolines based on the hydrocarbazole framework have been well established, the construction of their oxygen analogues, the fused hydrodibenzofurans, such as that shown in the thebinan type natural product (Figure ), cannot be achieved by existing methods. Herein, we report a distinct strategy via semipinacol rearrangements for the synthesis of a diverse range of functionalized hydrodibenzofurans.…”

Investigation of the acid/base behaviour of the opium alkaloid thebaine in LC-ESI-MS mobile phase by NMR spectroscopy

“…At more remote locations within the molecule, the chemical shift differences between the analogous H atoms on the epimers are less profound and the two separate signals cannot always be observed by simple inspection of the 1D 1 H NMR. However, assignments of signals on NMR spectra were made in reference to previously published analyses [10][11][12][13] and use 2D HH and HC COSY to support these conclusions. The 1 H NMR spectrum of thebaine in an 80 : 20 v/v D 2 O/CD 3 CN solvent mix containing 1% CD 3 COOD (figure 3a) indicates the presence of two epimeric forms in an approximate ratio of 58 : 42.…”

“…[ 10 ] reported the 13 C spectra for morphine alkaloids thebaine and sinomenine. In 1984, Theuns et al [ 11 , 12 ] analysed the structure of thebaine using both 13 C and 1 H NMR and most recently Caldwell et al . [ 13 ] reported the configurational analysis of thebaine and codeine using 13 C and 1 H NMR in 1996.…”

“…In 1975, Terui et al [10] reported the 13 C spectra for morphine alkaloids thebaine and sinomenine. In 1984, Theuns et al [11,12] analysed the structure of thebaine using both 13 C and 1 H NMR and most recently Caldwell et al [13] reported the configurational analysis of thebaine and codeine using 13 C and 1 H NMR in 1996. In this article, we report experiments which were performed to analyse structural behaviour in a range of solvents which replicate the changes in mobile phase composition encountered by the thebaine analyte during analysis by LC-ESI-MS.…”

Complete 1H, 13C, and 15N assignments of the minor isomer of codeine N‐oxide

“…[1] In this work, an additional impurity was observed with the same m/z but in a lower amount, about one tenth of the known and commercially available N-oxide 2. This phenomenon has been described with thebaine, [2,3] but according to our knowledge, N-oxide 3 has not been characterized yet. Unlike thebaine, codeine holds a hydrogen atom on position 14 that might be influenced by the presence of an Noxide and might help to assign nitrogen stereochemistry.…”